Firefox Support Forum

Can't connect with the just downloaded version 66.0.4 to virtually any site - not to Google, not to NYT, not even to Mozilla - Firefox won't accept ANY certificate! Following errors appear (examples): "Did Not Connect: Potential Security Issue Firefox detected a potential security threat and did not continue to addons.cdn.mozilla.net because this web site requires a secure connection. What can you do about it? addons.cdn.mozilla.net has a security policy called HTTP Strict Transport Security (HSTS), which means that Firefox can only connect to it securely. You can’t add an exception to visit this site. The issue is most likely with the web site, and there is nothing you can do to resolve it. If you are on a corporate network or using anti-virus software, you can reach out to the support teams for assistance. You can also notify the web site’s administrator about the problem.

Or: Warning: Potential Security Risk Ahead Firefox detected a potential security threat and did not continue to www.nytimes.com. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details. What can you do about it? The issue is most likely with the web site, and there is nothing you can do to resolve it. If you are on a corporate network or using anti-virus software, you can reach out to the support teams for assistance. You can also notify the web site’s administrator about the problem.

The explanation is as follows: Someone could be trying to impersonate the site and you should not continue. Web sites prove their identity via certificates. Firefox does not trust www.nytimes.com because its certificate issuer is unknown, the certificate is self-signed, or the server is not sending the correct intermediate certificates. Error code: SEC_ERROR_UNKNOWN_ISSUER

No problems whatever with other browsers. I'm sending this with Safari.

My images look all glitched out and scrambled. It wasn't like this before, and I don't remember if I changed anything in my about:config.

I've included what they look like.

Hello,

I have had a few websites not work properly with Firefox and have needed to open my backup browser (Avast Secure Browser) to use those websites.

Right now it is FedEx that comes to mind again as I kept checking for tracking of packages shipped to me since receiving the tracking info. I queries consistently returned the error message "Unfortunately we are unable to retrieve your tracking results at this time. Please try again later."

Thinking maybe the website was having issues or maintenance (and forgetting I had the same issue with FedEx website the last time I tried tracking there in Firefox), I kept "trying again later".

Then I opened my Avast browser and pasted the same url there and, sure enough, received this report on the display:

Travel History Date or Time City & State Status Monday, April 18, 2022 9:47 PM SPARROWS POINT, MD Departed FedEx location Sunday, April 17, 2022 1:49 PM Shipment information sent to FedEx

I have tried disabling the extension NoScript as well as turning off the "Enhanced tracking protection" and allowing permissions for the FedEx site with no improvement.

I copied and pasted the RAW data as well as the text version from the "about:support" page to send you.

Any suggestions to fix this?

Thank you, Keith McNabb

I got a notification that Yandex is no longer supported and my default search engine was changed to Google?

Why does Firefox care of which search engine I use? Why I can't use Yandex? I tried to add it again but it requires to install an addon for search engines and there's no addon for Yandex search.